Automatic system for collecting, weighing and releasing solid particles

Abstract

A automatic system for the capture, weighing and expulsion of solid particles, consisting of an airtight weighing chamber, inside which there is an inner container in which the particles entering the chamber through an entrance duct are collected. Said container transmits its weight to a weighing sensor, also located inside the weighing chamber but not in contact with the walls of the chamber. Once weighed, the sample is expelled from the chamber by the injection of compressed air. The system can be directly applied to determine the mass flow of solid particles in pneumatic transport ducts by integrating it into automatic sampling systems, and also gives a signal which can be integrated in regulating loops for the control of said flow.

Description

BACKGROUND OF THE INVENTION1. Field of InventionThere are numerous industrial processes which require the transport of solids through ducts using a carrier gas steam. Examples are the food industry, the pharmaceutical industry and, especially, combustion processes using solid fuel, such as power plants, cement factories and blast furnaces.Although for gases and liquids there has traditionally been a wide variety of equipment for continuous measurement of the mass flow through ducts, in the case of pneumatically transported solids, it is only in recent years that promising technologies have been developed for determining this parameter.The importance of measuring the mass flow of solids depends on the particular process involved. For coal-fired power stations this measurement is of vital importance from the point of view of the performance and operation of the plant and the emission of pollutants.Most coal-fired power stations use direct fuel feed systems. In these systems, the coal ...

AI Technical Summary

Benefits of technology

The system to be patented may be integrated in automatic particle sampling equipment based on any of these international standards, making up a system which makes it possible to carry out continuously measurement of the mass flow of solids transported pneumatically through a transport duct.

It needs no calibration using comparative measurements. Non-extractive measuring equipment carries out indirect measuring which is related to the particle flow through laborious calibrations using manual reference systems. In this aspect, the system described, associated with automatic portable sampling equipment, makes it possible the automatic execution of calibration routines for these measuring systems.

Problems solved by technology

The advantage of this method, in comparison to the others, is that it aspirates isokinetically at all points of the section, and its main disadvantage is the length of time needed for the sampling.

The disadvantage of this system is that it produces results by indirect measurement of the weight of the particles by determining the volume of the sample.

This may give rise to significant errors in the case of changes in the density of the solid or distribution of the size of particles, requiring continuous adjustment of the equipment to guarantee the quality of the measurement.

These measurement systems have the disadvantage of not being very precise and accurate, due to the fact that they are sensitive to parameters such as the humidity content of the mixture, the size of particles and the phenomena of segregation in the ducts.

In addition, they require periodic calibration using comparative measurements carried out using extractive methods, and do not allow for the obtention of a sample for later laboratory analysis.

However, these devices, in addition to having other aims, lack, among others, the characteristics related to the particle expulsion system.

All of this means that at present none of these technologies has reached a sufficiently robust state for large-scale industrial implementation.

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